In the heart of a major European tunneling project, contractors faced the daunting challenge of stabilizing unconsolidated ground while maintaining tight schedules. Traditional casing systems were time-consuming and costly. The solution came from SupAnchor®, a global leader in geotechnical reinforcement, whose R thread self-drilling hollow anchor system enabled drilling and grouting in a single operation, slashing installation time and enhancing safety.
The self-drilling anchor system with R thread is engineered to combine three critical functions into one tool: a sacrificial drilling rod, an injection tube, and a reinforcing bar. This "3-in-1" principle eliminates the need for a separate casing, allowing simultaneous drilling and grouting in unconsolidated or cohesive soils. The result is a dramatic reduction in construction time and labor, especially in tunneling and slope stabilization projects where overburden is loose and prone to collapse. The R thread, designed and manufactured in accordance with ISO 10208 and ISO 1720 standards, ensures quick on-site connection and installation, further streamlining the anchoring process. This standardization also guarantees compatibility with a wide range of accessories, from nuts and couplers to plates, making it a versatile self drilling anchor bolt for any geotechnical challenge.
SupAnchor's R thread series offers a comprehensive lineup of hollow bar anchor models, each tailored to specific load and ground conditions. The table below presents key parameters for four popular models, highlighting the balance between weight, ultimate load, and yield strength.
| Model | OD/ID (mm) | Ultimate Load (kN) | Yield Load (kN) | Weight (kg/m) |
|---|---|---|---|---|
| R25N/12 | 25/12 | ≥200 | ≥150 | 2.30 |
| R32L/22 | 32/22 | ≥250 | ≥200 | 2.75 |
| R32N/20 | 32/20 | ≥280 | ≥230 | 2.85 |
| R32S/17 | 32/17 | ≥360 | ≥280 | 3.50 |
Beyond these, the series expands into R38 and R51 classes, with models like R38/550 and R51/1000 offering ultimate loads exceeding 1000 kN. This scalability makes the self drilling anchor system suitable for everything from minor slope stabilization to deep tunnel forepoling. All bars are produced from high-grade steel per EN10083-3/EN10025, with elongation properties (≥6% A100mm) that provide excellent ductility – a critical feature in seismic zones or ground with potential movement. The hollow core not only acts as a grout conduit but also reduces weight, enabling easier handling and longer anchor lengths up to 8 meters per single piece.
The longevity of a drill-and-grout bolt is paramount in aggressive environments. SupAnchor addresses this with three anti-corrosion options. Hot-dip galvanizing (HDG) provides reliable protection for dry to mildly humid conditions, meeting the needs of standard tunnel interiors or inland slopes. For moderate corrosion risk, such as near industrial plants or permanently damp soils, the SupCoating system layers an epoxy coating over HDG, creating a dual barrier that resists chemicals and moisture. In the most severe settings – coastal structures, saline groundwater, or chemical processing plants – stainless steel anchors guarantee decades of service without degradation. This tiered approach allows engineers to specify the exact geotechnical reinforcement system their project demands, balancing performance with cost.
The versatility of the R thread self drilling anchor bolt is evident in its wide application spectrum. In tunneling, it is used for face support, radial bolting, and forepoling in soft ground conditions where immediate support is critical. The ability to drill and grout in one pass prevents borehole collapse and ensures full encapsulation of the bar, resulting in higher pull-out resistance. In ground engineering, slope stabilization projects benefit from the self drilling hollow bar anchor's rapid installation, especially on steep terrains where conventional drilling would be hazardous. Retaining walls and foundation reinforcements also use this soil nail system to counteract lateral earth pressures. Emergency repairs in collapsing soils or after landslides have seen the system deployed as a ground anchor bolt factory solution, enabling quick mobilization and immediate loading. With over 39 million meters installed globally, SupAnchor's hollow bar anchor has proven its reliability across all types of unconsolidated and cohesive ground.
As the world invests heavily in transportation networks, urban underground spaces, and renewable energy foundations, the demand for efficient and safe anchoring technologies is soaring. The self drilling anchor system reduces construction cycles by up to 50% compared to cased drilling, directly lowering project costs. Moreover, the enhanced safety – fewer manual interventions and no need for temporary casings – aligns with modern occupational health standards. Major infrastructure projects, from Alpine tunnels to Southeast Asian metro systems, have adopted this drill-and-grout bolt technology to meet tight deadlines without compromising ground stability. Analysts note that the geotechnical reinforcement system market is poised for steady growth, driven by urbanization and climate-resilient construction, and SupAnchor’s R thread series is well-positioned to lead this charge.
SupAnchor® has built its reputation on a foundation of professional engineering, innovative design, and collaborative client relationships. Every self drilling anchor bolt in the R thread series is a product of extensive R&D, tested against ISO 10208 and ISO 1720 standards to ensure global compatibility. The company’s manufacturing facilities employ rigorous quality control, from steel selection to thread machining, guaranteeing consistent performance batch after batch. Having supplied anchors for thousands of projects – including contracts with major tunneling contractors and government infrastructure agencies – SupAnchor has become a trusted name. Their commitment to providing a complete geotechnical reinforcement system, from nuts and couplers to tailored anti-corrosion coatings, makes them more than a ground anchor bolt factory; they are a partner in engineering success. As the company continues to innovate, introducing new models like the R38/820 and R51/1200, the future of ground support looks stronger and more reliable than ever.
SupAnchor's R thread self-drilling hollow anchor system has surpassed 39 million meters globally, delivering safer, faster drilling-and-grouting in tunnels and slopes. Discover its technical advantages and industry impact.
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